1. Field of the Invention
The present invention relates to an air conditioning system using a vapor compression-type refrigerating apparatus for moving heat on a low-temperature side to a high-temperature side, the air conditioning system being effective when applied to an automotive air conditioning system combined with a heater that makes use of waste heat generated in a vehicle.
2. Description of the Related Art
In the automotive air conditioning system combined with the heater which makes use of waste heat produced in a vehicle, as the amount of waste heat is small and the temperature is low at the time of a so-called cold start that results immediately after the start of an engine (an internal combustion engine) which constitutes a driving source for the vehicle, a sufficient heating capability cannot be obtained.
When the amount of waste heat is small and the temperature is low, in other words, when the temperature of engine coolant is low, a high-temperature refrigerant (hot gas) discharged from a compressor of the vapor compression-type refrigerating apparatus and not yet cooled is introduced into an inner heat exchanger so as to complement the heating capability (for example, see Japanese Unexamined Patent Publication No. 11-257762).
Incidentally, as has been described above, as the hot gas is introduced into the inner heat exchanger while maintaining its high-temperature and high-pressure state, the speed of the refrigerant which passes through the inner heat exchanger is relatively high.
Due to this, there is caused a risk that a relatively loud refrigerant noise is generated while complementing the heating capability with the hot gas.